More and more allergic children

For the last ten years, hay fever and eczema have been booming among the younger ones. In contrast, asthma has stabilized. Will these observations allow us to better prevent these diseases tomorrow? Some answers.

Hypotheses but few answers

In 1991, researchers from around the world participated in the international study on childhood asthma and allergies (known as ISAAC). The aim was to determine the proportion of people affected by asthma, hay fever and eczema. More than ten years later, Innes Ahser's team at the University of Auckland (New Zealand) To determine the course of these diseases.

Not an asthma but asthma!

The researchers followed close to 200,000 children aged 6-7 and over 300,000 aged 13-14 years from more than 50 countries including South Africa, Brazil, Iran, Canada, New Zealand or the United Kingdom. And the results confirm what was feared ... Trends to increase are more frequent than declines and more often concern younger.

This allergy boom mainly affects eczema for the younger and hay fever for the two age classes studied. But while previous studies have highlighted the increase in asthma among 13-14 year olds, the trend seems to be reversed.

Only the Asia-Pacific regions and India show an increase in the three diseases.

The authors believe that these new data can have a direct impact on the health policies of different countries as well as on the understanding of these diseases. But on this last point, the hypotheses have not changed for several years: changes in children's environment, especially urbanization, increase the susceptibility to develop allergies.
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Both external and domestic air pollution would affect the sensitivity and / or development of the lungs of the children, thus favoring respiratory pathologies.2 At the same time, a too clean environment could, through a lack of infectious stresses, prevent the maturation of the immune system of the newborn and Thus exposing it more easily to allergies.

Several studies support this hygiene thesis, in particular those demonstrating that children in nurseries have more infections but less allergy, in contrast to babies born by Caesarean section who have not been in contact with vaginal germs ...

As early as 1995, Fernando Martinez believed that asthma did not conceal a single disease but several different entities.3 This hypothesis is taken up by Professor Sally Wenzel of the University of Colorado, 4 who tries to characterize more specifically, asthma. This approach would make it possible tomorrow to better identify each syndrome, to better understand its mechanisms and therefore to take better care of them.

The editorial of Lancet even wonders whether, in the end, asthma is not the manifestation of different affections rather than a specific pathological entity. Absurd, do you think? Not so sure ! Until the 19th century, fever was considered a disease and not a symptom. Is it possible that asthma will experience the same demotion in 20, 30 or 50 years?

1 - The Lancet 2006, 368: 733-743; 2 - J Expo Sci About Epidemiol. 2006 Jan, 16 (1): 49-55, 3 - NEJM 1995 (3), 332: 133-138, 4 - Lancet. 2006c68 (9537): 804-13; 5 - The Lancet 2006, 368: 705